California has a very long coastline with many, many beaches. Of the 11 repeat offenders listed, 4 were in the small and confined area around the town of Avalon on Catalina Island. 6 spots were along Doheny State Beach located between Dana Point and San Clemente. Doheny is a long time offender. But I'm surprised that several others were not listed. Such as the beach where the Calif portion of the notorious Tijuana River empties into the ocean, Surfrider Beach in Malibu, and McGrath State Beach at the mouth of the Santa Clara River in Ventura County. Run-off in creeks or rivers emptying in to the ocean are a common source of pollution. During much of the year in SoCal, rains are infrequent, so when it does rain, all the accumulated, built-up crap and chemicals are suddenly washed into the sea. Even the Rincon point break south of Santa Barbara has had problems from the septic tanks of the nearby homes.